This proposal is a competitive renewal of a R25T Cancer Education and Career Development Program for postdoctoral training in Genetic and Molecular Epidemiology of Cancer (GMEC). The current era of cancer research is providing extraordinary tools for understanding the genetic and environmental causes of carcinogenesis. Using these tools to their fullest extent requires input from teams of scientists with a mixture of backgrounds, including molecular biology, oncology, medicine, genetics, epidemiology, and biostatistics. Individuals with trans-disciplinary education across these fields are crucial to the success of such teams. In particular, they can serve as the conduit for the integrated work necessary to accomplish some of the most promising research. However, the focused nature of most training opportunities provides limited opportunities for investigators to obtain the knowledge that bridges these disciplines. To address this issue, we propose continuing the current GMEC training program. The overall specific aim of this program is to offer a set of instructional and research opportunities to exceptional postdoctoral candidates in order to promote their careers as independent researchers in the interdisciplinary field of genetic and molecular epidemiology of cancer. Mentors and research training opportunities will continue to come from major academic and research institutions in the San Francisco Bay Area, including the University of California San Francisco and Berkeley, Kaiser Permanente, Stanford University, and the Northern California Cancer Center. This program is uniquely suited to the R25T grant mechanism because it trains scientists at the intersection of multiple distinct fields. More specifically, the GMEC program blends together in a highly interactive fashion a group of mentors and trainees from cancer research, molecular biology, genetics, epidemiology, and biostatistics. The program is defined by three main components: 1) a specialized core curriculum that covers the key disciplines and their intersections; 2) additional educational experiences to complement their research and educational background and interest; and 3) focused research projects with multiple mentors. Each trainee will also be required to extend their research experience by writing a mock NIH proposal. Individuals trained in this program will have the skills vital to deciphering the causes of cancer, ultimately providing valuable knowledge regarding the prevention and treatment of this complex disease.